Exhaust-valve for steam-engines



(No Model.) Q 2 Sheets-Sheet 1. B. OARLEY & W. W. EVANS.

EXHAUST VALVE FOR STEAM ENGINES.

No; 247,241. Patented Sept.- 20,1881 I (Nd Model.) 7 2 Sheets-Sheet 2. B. CAR-LEYXE W. W. EVANS.

EXHAUST VALVE FOR STEAM ENGINES.

No. 247,241. I Patented Sept. 20,1881.

III/II/ ///IIIIIIIIIIII WI/[III III/II Mlizesses UNITED STATES BENJAMIN OARLEY AND .WILLIA M EVANS, ()F PATERSON, NEW JERSEY.

PATENT OFFICE.

EXHAUST-VALVE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 247,241, dated September 20, 1881. Application filed December 30, 1880. (No model.)

1' all whom it may concern Be, it known that we, BENJAMIN CARLEY and WILLIAM W. EVANS, both of'Paterson, in the county of Passaic and State of New Jersey, have invented certain new and useful Improvements in Exhaust Valves and Ports for while working steam expansively.

The invention consists in a novel combination, in an engine, of an lndependent exhaustvalve, an auxiliary cylinder and piston or pistons for actuating said valve, a steam-chest separate from said auxiliary cylinder, and a valve-seat having init main steam-ports and auxiliary steam-ports for admitting steam to act upon said piston or pistons, and a main valve controlling both said main steam-ports and said auxiliary steam-ports, whereby provision is aft'orded for opening widethe exhaustvalve at the beginning of the stroke of the engine-piston and leaving it wide open during the whole or the greater part of the stroke.

In the accompanyingdrawings,Figure lrepresents a plan viewot' a locomotive-cylinder and main steam-valve and a section through an auxiliary cylinder in which are the exhaustvalve and its actuating-pistons. Fig.2 represents a transverse section upon the dotted line :0 00, Fig. 1; and Fig. 3 represents a plan and horizontal section upon the dotted line 3 3 Fig. 2, themain steam-valve being removed.

Similar letters of reference designate corre sponding parts in all the figures.

A designates a locomotive-engine cylinder, having a valve-seat, A, upon its upper surface, and constructed with two main steamports, a a, leading from near the middle of the cylinder to each end thereof.

B designates the steam or valve chest, and O designates a slide-valve working upon the seat A to control the passage of steam through the main steam-ports. This usual exhaust-port between the two steam-ports a a is not employed, and hence the valve 0 need have no exhaust-cavity or D, but consists simply of a flat-faced piece of metal actuated in the usual way by a strap or yoke or other suitable means.

Steam is supplied to the steam or valve chest.

B in the usual way by an inlet-passage, B, from the boiler.

D designates a small auxiliary cylinder parallel with the main cylinder A, and communicating with the two ports a a by means of passages or ports I) b, and in said cylinder D, opposite or ranging with said passages or ports I) b, are other ports, 0 c, which communicate with the exhaust chest or chamber E.

The exhaust-valve F, in this example of our invention, consists of twopiston-head's, each controlling one of the ports I) and its opposite port 0, but the exhaust-valve might consist of a slide-valve, the ports being suitably arranged.' The exhaust-valve F is actuated by pistons G, working, in opposite ends'of the auxiliary cylinder D, and the pistons and valve are all connected by a common rod, H, fitting in guides formed in the heads D of the auxiliary cylinder D, so that the valve and its actuating-pistons all move in unison.

Upon the 'rod H, between the pistons G and the adjacent heads D, are springs I, which cushion the pistons G and prevent shock as they'areimpelled in either direction by the action of the steam.

Steam is admitted to act upon the pistons G by means of passages 01 d, extending from each end of the auxiliary cylinder, and terminatin g in auxiliary steam-ports e e in the valveseat A, at one side of and in proximity to the main steam-ports a a.

The main steam-valve G has at one end an extension, 0, of greater length than the valve, and which covers the ports 0 e, as clearly shown in Fig. 1. In the extension 0 of the valve (J is a port,f, which by the movement of the valve is brought opposite the ports 6 c alternately, and admits steam first to one end and then to-the other end of the cylinder D, to act alternately upon the pistons G and reciprocate the exhaust-valve F. After being admitted to the auxiliary cylinder D to act upon one piston G, it is necessary that the steam should be exhausted to enable the valve to be moved freely when the steam acts upon the other piston, and this is effected by providing exhaustnotches s in the cylinder D, through which steam is'exhausted into the exhaust-chamber E.

It is desirable that the exhaust-valve F should have a slight lead over the main valve 0, so that a free exhaust will be afforded the moment the main piston commences its stroke. To effect this the ports 6 e are made a little nearer together than are the ports a a, as seen clearly in Fig. 3, and by reference to Fig. 1 it will be seen that the one of the ports 6 which is partly open through the valve'port f is open to a greater extent than the opposite port a, which is also partly open. In Fig. 1 the exhaust-valve F is represented as having already been moved toward the bottom of the drawings, opening communication between one pair of ports I) c and cutting off communication between the ports of the other pair by one of the piston-heads F covering both ports. The exhaust-valve F is thus thrown wide open just before the main piston commences its stroke, and remains wide open during the wholestroke, whether the engine is working expansively or not; and it will be seen that the main valve may be set to get any degree of expansion \vithoutinterfering with the exhaust, because after being once moved to open the exhaust from one end of the cylinder the exhaust-valve remains stationary until it is moved to open the exhaust from the opposite end of the cylinder.

Although we have shown two pistons G, upon which steam acts alternately, asinglepiston acted upon by the steam alternately on opposite sides might be substituted for the two pistons.

We are aware that it is old to combine with the main cylinder of an engine an auxiliary cylinder containing piston or puppet valves, which control both the admission of steam to and its exhaust from the main cylinder, and which are all fixed upon a common valve rod or stem, and hence we do not claim such construction as of ourinvention.

What we claim as our invention, and desire to secure by Letters Patent, is-

1. The combination, in a steam-engine, of an independent exhaust-valve, an auxiliary cylinder, and a piston or pistons for working said valve, a steam-chest separate from said auxiliary cylinder and containing a valve-seat having in it main steam-ports and auxiliary steam-ports for admitting steam to act upon said piston or pistons, and a main slide-valve controlling both said main and auxiliary steamports, and serving to admit steam both to the main cylinder of the engine and to the auxiliary cylinder to act upon said piston or pistons, substantially as specified.

2. The combination of the main cylinder A and auxiliary cylinder D, provided with ports a a, e e, and b b and c 0, the slide-valve (J, containing the portf, and the exhaust-valve F and pistons Gr, all substantially as specified.

BENJAMIN OAKLEY. I WILLIAM W. EVANS.

Witnesses:

FREDK. HAYNES, A. O. WEBB. 

